Sürdürülebilir Kalkınma Amaçları
Yazarlar
Yayınlar
- MakaleAçık Erişim2026Scopus SJRQ1Multi-parameter hydrodynamic analysis of pulsation frequency and waveform effects in a conical spouted bed: A CFD study
Çutay, Arif; Tozlu, Alperen; Kütük, Begüm; Özahi, Emrah
The hydrodynamic behavior of spouted beds is strongly influenced by inlet flow conditions, particularly under pulsating operation. In this study, a three-dimensional Eulerian–Eulerian two-fluid model coupled with the kinetic theory of granular flow was used to investigate the effects of pulsation frequency and waveform on the hydrodynamics of a conical spouted bed. Steady, sinusoidal, pulsatile, and square-wave inlet conditions were analyzed at 1, 3, 5, and 10 Hz. A multi-parameter evaluation framework was applied by combining spout height, temporal stability, axial gas and particle velocity distributions, and mixing characteristics. Spout height was determined using the connected αs=0.05 iso-contour, while temporal behavior was quantified through the mean spout height, standard deviation, coefficient of fluctuation, and fluctuation range. The results show that spout performance depends not only on instantaneous inlet velocity but also on the persistence of axial momentum transfer. Although the steady condition and some high-penetration pulsating cases produced relatively large instantaneous spout heights, they did not necessarily provide the most favorable hydrodynamic behavior because of rapid velocity decay, stronger fluctuations, or reduced structural coherence. Pulsation at 3 Hz provided the best overall balance by sustaining particle transport and improving temporal stability. The 5 Hz cases enhanced mixing but exhibited larger fluctuations, whereas the 10 Hz cases produced weaker and less coherent spout structures because of rapid attenuation of the imposed oscillations. Overall, the proposed framework demonstrates that spouting performance should be evaluated through the combined effects of penetration, stability, momentum persistence, and mixing.
AtıfOpenAlex1
İncele - MakaleAçık Erişim2026Scopus SJRQ1Comparative thermal and hydraulic performance of Type-22 panel radiators under continuous and pulsating flow
Köksal, Hüseyin; Ceviz, Mehmet Akif; Muratçobanoğlu, Burak; Mandev, Emre
Pulsating water-side flow has been proposed as a radiator control strategy to enhance heat emission at low supply temperatures, yet device-level studies rarely quantify thermal gains together with hydraulic costs under matched baselines. This study experimentally investigates the coupled thermal and hydraulic response of a PCCP Type-22 panel radiator operated under continuous and on–off pulsating flow regimes. A dedicated test loop was developed using a temperature-controlled hot-water tank (50 °C setpoint) and an Arduino-based driver to impose repeatable pulsation, while measuring inlet/outlet temperatures, instantaneous flow rate, pump electrical energy, and spatiotemporal surface temperatures via infrared thermography. The results show that increasing the continuous flow rate provides the highest absolute heat output, but at the cost of increased pumping energy. In contrast, pulsating operation improves the thermal–hydraulic balance by increasing heat delivery relative to the reference case while reducing pump energy consumption. Among the tested pulsating cases, short-period pulsation produced the most favorable behavior by maintaining a warmer and more spatially stable radiator surface. Longer off-periods promoted deeper surface cooling, reduced the effective emitting area, and weakened the thermal benefit of pulsation. Infrared thermography confirmed that the pulsation period strongly affects surface-temperature uniformity and temporal stability. Overall, short-period on–off pulsation emerges as the most favorable operating mode when the objective is to increase heat delivery while lowering pumping energy in PCCP-type radiators.